Glossary of Terms
Words contained in " " are taken from the Forests Act or are terms used in the body of this Standard and defined in this glossary. The definitions give meaning to terms applied to SFM pursuant to the Forests Act.
Accuracy How close a sample estimate of a population (e. g. sample estimate of "stand" volume) is to the true population value. We don't usually know the true value; sample accuracy is normally judged from sample "precision".
Advanced growth Young trees that have become established naturally before any harvesting of older trees is undertaken. For the purpose of this standard, advanced growth is defined as "saplings" and "poles".
Allowable harvest The quantity of timber that may be harvested annually, usually expressed on a species basis per unit area (e. g. "m3/ha" of red beech) or as a total annual quantity for the forest area as a whole. In the case of an SFM Permit the allowable harvest is the volume of timber available for harvest over the term of the Permit.
Amenities See "Amenity values"
Amenity values "Those natural or physical qualities and characteristics of an area that contribute to people's appreciation of its pleasantness, aesthetic coherence, and cultural and recreational attributes".
Anthropogenic Caused by human activity (e. g. modification of a forest by harvesting or burning of trees).
Basal area The area of the cross section of the stem of a tree at breast height (1.4m above ground level) inclusive of its bark. Basal area, expressed as "m2 /ha" is often used to provide a measure of site occupancy of a species or group of species.
Bias A systematic error (of measurement) that affects all measurements the same way. A sample mean may be precise but biased; that is, the sample measurements are clustered closely about their mean but do not represent the true value.
Biodiversity The numbers and distribution of all flora and fauna from time to time existing on the land.
Broadleaved Used in the Forests Act in the terms "shade-tolerant and/ or exposure-sensitive broadleaved hardwood species". A term applied to Angiosperms: trees and shrubs that reproduce by producing seeds in an ovary and having leaves of relatively large area. Distinguished in the Forests Act from (small leaved) "light demanding hardwoods" (also Angiosperms) such as beech.
Canopy gap A space on the forest floor not covered by the crowns of trees, created by the felling or death or toppling of a tree or a number of trees. The area defined by the vertical projection to the ground of the edges of the crowns of standing trees surrounding the canopy gap. Canopy gap area may diminish rapidly as the crowns of edge trees grow to occupy the gap, referred to as "gap infilling". As such "expanded gap" area is a more repeatable measure over time.
Composition The variety of species present within an area of forest.
Confidence limits The statistical way of indicating the reliability of an estimate calculated from (preferably) a random sample. Usually expressed as a value above and below the sample mean within which the true mean will lie, at a specified probability level for sampling. For example the volume of rimu in a forest may be estimated, on the basis of a sample measurement of trees, to be 100m 3 /ha + 10m 3 /ha at 95 percent probability level of sampling. The 95 percent lower and upper confidence limits are thus 90 m 3 /ha and 110 m 3 /ha and this range is the 95 percent "confidence interval". This means that the mean stand volume is between 90 m 3 // ha and 110m 3 /ha unless a one in twenty chance has occurred in sampling the forest. The wider the confidence limits, the less reliable the estimate is deemed to be.
Coupe An area of clear-cut (felled) forest where all trees are felled in the designated area.
Density The number of stems per unit area, usually expressed as stems per hectare (sph).
Directional felling Felling a tree in a pre-determined direction, usually with the aim of minimising damage to adjacent trees or advanced growth.
Disturbance Past events that have influenced the "composition" and history "structure" of a forest, both natural and anthropogenic.
Domestic stock Referred in the Forests Act as "stock". Taken to include, but not confined to, sheep, cattle, pigs, goats, deer and horses.
Estimate Usually derived from a measured sample (forest "inventory"). Used to quantify a characteristic of a population (e. g. stand volume). In respect of SFM Permits (Benchmark 1.1.1.2 (4)) "estimate" also includes predictions based on documented information pertaining to a similar forest or group of forests, or from a subjective assessment based on the knowledge and experience of the assessor, or both. In the latter two circumstances the estimate will therefore not be accompanied by confidence intervals and its reliability cannot be expressed in statistical terms.
Expanded gap The area calculated from measurement between the trunks of trees nearest to and surrounding the "canopy gap".
Exposure sensitive Tree species that are susceptible to damage to their foliage resulting from increased exposure to wind or frost (e. g. tawa on some sites).
Felling Cycle The interval between successive harvesting in a forest area.
Forest area That area within which harvesting will be undertaken and that is defined on a map attached to a registered SFM Plan or Permit.
Forest type A class of forest vegetation that is sufficiently distinct to require a different kind of management from that of other forest types.
Growth rate The annual or periodic increase in the dimensions of a forest variable or parameter (e. g. diameter and height or basal area and volume, respectively).
Harvest The act of felling a tree and removing all or part of that tree from the forest. Harvesting is not deemed to be complete until the "timber" has been removed from the "landholding".
Harvest rate The annual or periodic allowable harvest. May be expressed as m 3 /ha/ annum or m 3 /annum or m 3 /period for the "forest area". Defined in a registered SFM Plan as the annual allowable harvest from the "forest area". Defined in a registered SFM Permit as the volume of timber available for harvest over the term of the Permit.
Harvest The technical and administrative aspects of controlling regulation the quantity of timber harvested from the forest so that the "allowable harvest" is not exceeded.
Indicator A quantitative or qualitative variable that can be measured or described which when observed periodically demonstrates trends (e. g. the change in distribution or density of a plant or animal species).
Indigenous A species of flora or fauna that occurs naturally in New Zealand or arrived in New Zealand without human assistance.
Indigenous forest "land wholly or predominantly under the cover of land indigenous flora".
Industrial wood Applied to wood that is not of "sawlog" quality. Usually refers to wood suitable for production of pulp or other reconstituted wood products.
Inventory A survey of a forest area to provide information on forest species including but not limited to, information on the quantity of timber of commercial tree species present and their growth rates.
Landholding "Any right, title, or interest of any kind over any indigenous forest land in New Zealand, otherwise than by way of charge or security, by which indigenous timber may be harvested".
Light demanding Refers to tree species requiring relatively high levels of light for seedling survival, growth and recruitment into the forest canopy e. g. some beech species and "seral" species such as rewarewa, manuka and kanuka.
Low impact The management of forests in such a way that the techniques impacts on the forest from conducting "silvicultural" operations are minimal (e. g. the use of low ground pressure tractors to minimise soil compaction).
Merchantable That quantity of a tree assessed to contain timber volume "capable of being milled".
Micro-organism Includes algae, bacteria, fungi and viruses.
Modified forest Forest that as a result of previous harvesting or other human interference displays characteristics that differ from unmodified forest of the same type.
Natural values The attributes of the individual and interrelated biological and physical components, and processes of an area (this is further discussed under Criterion 2).
Owner "Any person who owns a "landholding" and includes (landowner) the owners of any landholding where there it is owned by two or more persons and a group of owners of landholdings who are operating under the same Sustainable Management Plan".
Periodic harvest The maximum "allowable harvest" permitted for a given period, expressed either on a per hectare basis or for the forest area as a whole (e. g. m 3 /ten year period).
Permanent sample A permanently marked area within which the tree plot (PSP) species and other forest variables are marked and measured at periodic intervals to provide estimates of forest growth and other forest change.
Pest While not defined in the Forests Act, pests are taken to include wild animals (pursuant to the Wild Animal Control Act, 1977) including feral deer, possums, goats and pigs, where they are in sufficient numbers to seriously impact on natural values and forest regeneration. Introduced animals such as the mustelids (ferrets, stoats and weasels), rats, and insects such as wasps are also regarded as forest pests.
Podocarp Conifers (cone bearing) belonging to the Podocarpaceae family, often referred to as softwood tree species. Of these, rimu is the most important timber-producing podocarp and is one of the most widespread tree species in New Zealand.
Pole Refer "size class". Precision The degree of agreement of a series of measurements. Usually expressed as the standard error of the mean (a statistical term) or as confidence intervals, sample precision describes the size of the deviation of the of sample values about their own mean.
Predators Pest species that predate (kill and feed on) fauna including native birds and invertebrate species. Includes possums, mustelids, rats and wasps.
Probable Limits Confidence limit expressed as a percentage of the of Error (PLE) sample "estimate" i. e., mean. A term only in use in New Zealand.
Recruitment Trees that enter a particular size class or classes in a given time period (e. g. poles growing into the 30 - 39cm tree size class in a given time or "recruitment" period.
Representative Synonymous with "indicator" species. species
Riparian In relation to vegetation growing in close proximity to a watercourse, lake, swamp or spring and often dependent on its roots reaching the water table.
Sample A part of a population consisting of one or more sampling units selected and measured as representative of the whole.
Sapling Refer "size class".
Scarification Disturbing the forest floor and exposing bare mineral soil to provide suitable conditions for the germination of natural seedfall.
Seedling Refer size class.
Senesce( nt) Trees that are growing old and have passed the period of maximum growth.
Seral Part of a sequence of vegetation succession. Usually applied to forest species that colonise disturbed sites (e. g. resulting from natural events causing canopy gaps, or forest harvesting, fire etc.) and are succeeded by other, usually taller-stature species that germinate and grow under the shelter of the seral species (e. g. manuka and kanuka).
Shade tolerant Tree species that display the ability to regenerate and grow in shaded conditions (e. g. tawa is one of New Zealand's most shade tolerant tree species).
Silviculture The management of trees to provide timber (includes (silvicultural) planting, pruning, thinning, and harvesting).
Size class Usually diameter classes used to describe stand structure and the merchantable element of the forest (e. g. seedling - 30cm high to 1.4m high; sapling - 1.4m high to 9.9cm dbh); pole - 10cm dbh to 19.9cm dbh; small tree -20cm dbh to 29.9 cm dbh; tree -30 cm dbh to 39.9cm dbh, 40cm dbh to 49.9cm dbh etc.
Smallwood A term applied to roundwood of dimensions too small to be milled and often utilised for posts, poles or firewood.
Stand A community, particularly of trees, displaying sufficient uniformity as regards composition, spatial distribution and structure so as to be distinguishable from adjacent communities (e. g. a forest area may consist of a number of differently aged stands of trees). Often loosely applied to the trees within a forest type.
Stand composition The variety of tree species present in a stand (or within (forest composition) a given forest type).
Standing The volume of the standing tree (usually inside bark), roundwood volume determined from a measurement of the tree dbh and height to a minimum small end diameter (commonly 15-20cm diameter or the point at which the main stem spreads into the crown) usually in conjunction with either a volume table or volume equation.
Stand structure The manner in which the tree species are arranged (forest structure) within a stand (or forest type) on a three dimensional basis (e. g. the presence and numbers of tree species in a range of height tiers (classes). The "reconnaissance" forest description methodology provides for the recording of all plant species along with an indication of their relative abundance within predetermined height tiers (refer Criterion 2).
Supplementary Planting of seedlings in the event that advanced growth planting/ restocking (of kauri, podocarp and shade-tolerant or exposure-sensitive broadleaved hardwood species) is judged to be insufficient, or where there is a failure of regeneration in beech or light demanding hardwood forest.
Timber "Includes trees when they have fallen, or have been felled, and whether sawn, hewn, split or otherwise fashioned and includes tree ferns, woodchips, timber products, and the roots and stumps of trees."
Tree Refer "size class".
Units of measure mm - millimetre cm -centimetres m - metre ha -hectare dbh - diameter at breast height (1.4m above ground level) m 2 /ha - square metres per hectare m 3 /ha - cubic metres per hectare sph - stems per hectare
Volume The volume of a tree or log, expressed as m3 .
Volume control Controlling the harvest from a forest by monitoring the volume (being standing roundwood volume) of timber selected and harvested.
Volume Equation A mathematically derived relationship permitting the (and volume calculation (or reading from a table) of the stemwood tables) volume (usually inside-bark) from the measurement of variables such as dbh and height.
Weed Undesirable vegetation, often comprising herbaceous plants, shrubs and ferns (may include indigenous species) that have the potential to suppress forest regeneration. Weeds such as gorse may establish along road edges from seed present in roading metal brought into the forest. "Adventive" weeds are those that appear outside their usual habitat. They may establish from windborne seeds or be carried into the forest on the undercarriage of vehicles and logging machinery. Adventive weeds are often herbaceous plants (e. g. pasture grass species, rushes etc). Where they occur in gaps created by, for example, coupe felling of beech, they are usually short-lived, becoming suppressed by the regeneration and growth of the new generation of trees.
Wild Animal Refer "pest".
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